Exercise Symptoms and Muscle Adaptations
Post-COVID patients often experience persistent symptoms such as fatigue, muscle pain, "brain fog," and PEM, where even minor physical or mental exertion can exacerbate symptoms. These issues significantly impact daily functioning and recovery.
Through a review of the literature, the researchers identified several changes in the muscles of post-COVID patients that may contribute to reduced exercise capacity. These adaptations offer critical insights into the underlying mechanisms of post-COVID and the challenges patients face.
Key Findings
- Post-COVID is associated with shifts in metabolism and muscle properties, which may explain why fatigue occurs more rapidly.
- The mitochondria, known as the cell's "powerhouses," function less effectively, resulting in muscles generating less energy and tiring more quickly.
- Impaired oxygen delivery to muscles—potentially caused by changes in the capillary network (small blood vessels supplying oxygen to muscles) and endothelial cells (cells lining blood vessels)—may worsen symptoms.
- Post-exertional malaise is likely aggravated by muscle tissue damage and the accumulation of immune cells in muscles after exertion, leading to muscle pain.
“While much research on post-COVID focuses on the immune system, our work highlights the role of muscle adaptations in long-term symptoms,” says muscle physiologist Wüst. “This could be an important step towards developing targeted treatments.”
Future Perspectives
The authors stress that the mechanisms behind PEM and long COVID are not yet fully understood, and no effective treatments are currently available to directly address these muscle-related problems. However, their findings provide important starting points for further research.
“Our goal is to support both patients and healthcare providers by shedding light on the causes of this complex condition,” adds Wüst. “We hope our findings will contribute to more targeted treatments and improved care for patients.”
For Patients and Healthcare Providers
The researchers recommend that patients consult with their healthcare providers to ensure physical activity remains within their limits and to avoid overexertion. In addition, patients who would like to learn more or have questions about our findings can contact specialised patient organisations.
Please read this explanation if you would like to learn more about what this research means for patients.
More Information
The full review article, "Skeletal muscle adaptations and post-exertional malaise in long COVID," is published in Trends in Endocrinology & Metabolism.